Fuse cartridge



Nava 13 1923. n `1,474,146

F. A. FELDKAMP FUSE CARTRIDGE Filed Aug. 123, 1919 AoRNEYs Patented Nov.13, 1923.

UNITED STATES FREDERICK A. EELDKAMP, `or NEWARK, NEW JERSEY.

EUsE CARTRIDGE'.

Application led August 23, 1919. Serial No. 319,303.

To all w 710m t may concern A Be it known that l, FREDERICK A. FELD-Kairr, a citizen of the United States, residing at Newark, in the-countyof Essex and State of New Jersey, haveiinvented certain new and usefulImprovements in Fuse Cartridges; and l do hereby declare the followingtobe a full, clear, and exact'description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had tothe accompanying drawings and tocharacters of reference marked thereon, which form a part of thisspecification. n

The present invention `has reference, gencrally, to improvements in'fuse cartridges.

The invention has for its principal object to provide a novel means, incombination with the general `fuse cartridge construction, adapted toreduce and relieve sudden internal pressure within the fuse container,due to a sudden blowing of the fuse. thereby preventing bursting orrupture of the container and other attendant dangers.

Other objects of this invention, not at this time more particularlyenumerated, will be clearly understood from the following d etaileddescription of the same. i

lilith the objects of my invention in view, the same consists.,primarily, in the novel construction of fuse cartridge hereinafter setforth; and, furthermore, the invent-ion consists in the novelarrangements and combinations of the various parts, as well as in thedetails of the construction thereof, all of which will be hereinaftermore fully de-V scribed and claimed.

The invention is clearly illustrated in the accompanying drawings, 1nwhich Figure l is a longitudinal section ofa fuse cartridge madeaccording to and embodying l the principles of my present invention;Figure 2' is an end elevation of the same; and Figure 3 is across-section through the same taken on line 3-3 in said Figure l.

Figure 4 is a longitudinal section of a slightly modified constructionof my novel fuse cartridge, Figure 5 is a longitudinal section of amultiple fuse cartridge embodyingthe principles of my present invention.

Similar characters of reference are employed in the herein abovedescribed views, to indicate corresponding parts.

It is well known that upon the blowing of the fuse element of fusecartridge by a short circuit, an internal pressure created `within thecartridge or container, which is due both to vaporization of the fusemetal, as wellv as to thee-Xpansion by the generated heat of air presentbetween granules of the filler usually surrounding the fuse. .This

pressure is of considerable magnitude, and

if not quickly reduced or relieved, may result in the bursting of thecartridge or at least in a serious rupture thereof. In order to relievethe internal pressure created by the gases resulting from thevaporization of the fuse, it has heretofore been customary to provideescape openings or vents in the ends of the ferrules, and in order thatthe granular filler substance should be prevented rfrom falling orpassing out through and passage of the gases therethrough, or as in thecase of4 wire mesh or perforated discs, the interstices therein becomeso clogged or choked up with the granular filler substance .that thepassages therethrough become impassable, thus counteracting the veryfunction of venting the gases and relieving internal pressure desired tobe accomplished. Even `in the event that the gases Clo-reach the ventopenings of the ferrules, and pass out.- wardly therethrough, the same`are in such a state of high ten'iperature, that there lis always dangerof igniting indammable material in theneighborhood of the fusecartridge. That such is thecase has been est-ablished by underwriterstests in numerous instances. i

,It is the primary object of my present invention to combine in, thestructure of a fuse cartridge a novel means whereby not only will thegases occurring after the blowing and vaporization of the fuse elementbe quickly liberated from the interior of the cartridge or container,but the same will also be quickly. reduced in temperature, all

of which `will result in a very rapid reduc-y tion of internal pressurewithin the cartridge or container, thusk rendering the fuse cartridgemuch safer in use, and assuring against bursting or rupturing of thesame under the conditions above mentioned. p

l/Vith, this object in view my novel construction ot fuse cartridgecomprises a suitable tubular casing 1 made ot some desired variety otinsulating material, the same heing closed at its respective ends bymeans ot metallic terrules 2, the same not only serving to close theinterior chamber 3 provided by the casing, but also serving aselectrical contact elements to be received in the clips provided torholding the tuse cartridge in use, and electrically connected in thecircuit to be served by the same. Centrally disposed relative to eachferrule 2, and secured to the enti walls thereof by solder or othersuitable tastenii c means are inwardly extending anchor studs or contactposts 4; to which are secured the respective ends et a i'use element 5mounted to extend longitudinally through the said interior chamber Theintermediate space of the chamber 3 about the luse element 5 is filledwith a granular filler-powder 6, such as is commonly employed in theconstruction oil ruse cartridges. Disposed in the end portions of thechamber 3, between the tiller powder and the end walls ot the lierrules.4, and extending for a `considerable or substantial depth, are layersot metallic wool T or .other metallic material adapted to provide ahighly porous mass, or a body of metallic material interspersed with amultiplicity of interconnecting interstices throughout its extent. Ilind that the substance which gives most er:n cellent results,considering` the purposes in view, is what is known as steel wool,although I do not necessarily limit myself to the use of this materialalone, since any metallic wool. the metal ot which possessesconuiaratively high melting point, or any metallic shavings, ilings orchips of comparatively high meltingpoint, which when massed togetherprovide the desired multiplicity ot interconnected interstices may beused, and will serve more or less successfully the purposes I have inviewY The cud walls oit the ierrules 2, against the inner sides oitwhich the said layers of metallic wool or the like abut, are providedwith a number of vent holes or per'torations 8. In some cases it may bedesirable to `re-enforce or strengthen the end walls of the terrules 2,in which case a disc 9 ot metal or other suitable material may bearranged and suitably secured against the inner side of Said end wallsot' the ferrules 2, said disc 9 being pro vided with vent holes orper'torations 10 to register or aline themselves with the vent holes orperforations 8 of the ferrules` all of which is more particularlyillustrated in figure l ot the drawings. While I have described thelayers 7 `of steel wool or other suitable material as disposed at eachend of the chamber 3 intermediate the filler powder 6 and the terrules2, itt desired.r the same may be omitted at one end of the chamber atone cud ol the chamber B, the vent holes or p rtorations 8 being omittedfrom said teil 'thus engaged by the said filler i'iovfder.

Referring now, more particularly, to lligure ol" the drawings, I haveshown therein how the principles o'li' my present invention may bwiriplied to a multiplo if'use cartridge, such, tor example, as is in myprior application for Letters-Patent, tiled March 31, 1917, and bearingSerial No. 158,809, result ing` in Patent No. 1,268,807. In this viewthe reference character 11 indicates the tubular casing having a linedterrule l2 at one cnil, and a movable vlerrule 18 at the opposite end.Arranged in that end oli the casing); bearing the niovable 'lier-rule 13is a plug 1st in which is imbedded the ituse contact pins 15 with whichthe contact element 16, carried by the niovahle fcrrule 18, may beselectivelyv engaged to brine` into the circuit any desired one ot thetuse elements 17 extending rcspectirely from said contact-pins l5. Suitable partition members 18 are provided to enclose each fuse-eleinent 17in its own individual compartment. Connected with said tired licrrule 12is an inwardly extending common contact-post 19 with which the severalfuse elements 17 are connected to electrically engage the same with saidlixcd terrule 12. rlhe )artition members 18 terminate short ot the endwall of said liXed lierrule 12 leaving an annular free space about theshank of said contact post 19. The several elements 17 are eachsurrounded in their respective compartments with the usual granularfiller powder 20, which also extends partially into the annular lireespace above mentioned. Arranged in said annular tree space between thefiller powder 2O and the end wall ot said fixed terrule l), is a layerot steel wool or the like 21, and the said end wall of the Fixed terruleis provided with one or more vent holes or pertorations 22.

lxfben a` 'luse cartridge constructed acrording' to the principles ol mypresent invention is blown, the heat expanded air and the gasef-,resulting trom the vaporization of: a portion oilz the. fuse metalimn'iediately gives risc to an internal pressure within the casing. Theexpanded air and gases are tmced by this pressure through the fillerpowder, and are driven into the layer of metallic wool or the likepenetrating and passing' through the interstices thereot` until the ventholes or perforations in the adiacent 'terrules are reached, throughwhich they are passed into the external atmospliere. By passing throughthe interstices inV said layer ot metallic material, the temperature otthe air and gases is quickly reduced by contact With the comparativelycool metal, and consequently the volume thereoi is diminished as theycool, thereby .immediately tending to reduce the pressure trom suchcause, as well as by the reduction ot' their volume due to the ejectionthereof' through the vent holes or pertorations of the terrules. Anotheradvantage of the layer oi? metallic wool or the like is that the same ismore or less elastic to its mass, and consequently cannot` be choked upwith filler powder, since the interstices termed extend in alldirections, and new openings or pas sages tor the gas open up aroundsuch particles ot powder as may possibly penetrate the metallic woolvlor a short distance, so that the may always `lind a point oli' escape.

l'n this respect my arrangement is much su perror to perforated or wiremesh washers or discs, the interstices of which all extend in onedirection so that the powder may very quickly penetrate the same andvquickly choke them up, thus obstructing the desired venting et the gas.Furthermore, the per- 'rorated orrwire mesh washers or discs do notsuccessfully bar the escape ot some powder therethrough when handlingthe fuse cartridges, whereas the layer of steel wool or the likeprovides such a multiplicity of devious passages that the powder can notpenetrate through the same in astraight line and consequently is soonblocked against escape. The periorate or wire mesh discs or washers donot provide a sutlicient mass of metal to have an appreciable coolingeffect on the heated gases.

The general result ot my novel structure is that the heated gases arequickly vented trom the interior ot the cartridge so that pressure uponthe latter is so reduced as to prevent rupture or bursting of the same;are quickly reduced in temperature before their iinal escape so thatlittle danger of ignitin inflammable material exterior of the cartridgeexistsgand are so cooled and reduced in pressure as to nally escapenoiselcssly through the said vent openings or pertorations ot theferrules.

My invention also contemplates the use of the steel wool or other likematerial in combination with suitable vents in the fuse containingcartridge even though the liller owderV is omitted ifrom the structure,an the iusc element enveloped only by the air con lined within thecontaining cartridge.

l claim y l. A fuse cartridge comprising a tubular container, metallicend ferrules closing the ends of said container, an internally disposedtuse element interconnecting said end lcrrules, a granular i'illervpowder enveloping said fuse element, at least one ot said end 'erruleshaving vent openings in its end wall, and a layer of metallic woolcapable ot rapidly conducting heat interposed between said vent openingsand said filler powder, said metallic wool having a comparatively highmelting point.

2. A. fuse cartridge comprising a tubular container, metallic endterrules closing the ends ot said container, an internally disposed tuseelement interconnecting said end ierrules, a granular filler powderenveloping said 'fuse element, at least one ot said end terrules havingvent openings in its end wall, and a layer of steel wool ol substantialdepth interposed between said vent openings and said ller powder.

3. In a device of the kind described, a containing cartridge, a fuseelement enclosed within said containing cartridge, said containingcartridge having vent means, a granular lille'r powder enveloping saidfuse element, and a layer of steel wool Yinterposed between said ventmeans and said filler powder.

4. In a device of the kind described, a containing cartridge, a fuseelement enclosed within said containing cartridge, said containingcartridge having vent means, and a layer of steel wool arranged withinsaid containing cartridge in back of said vent means.

In testimony, that l claim the invention set forth above l have hereuntoset my hand this 21st day of August 1919.

FREDERICK A. FELDKAMP.

Witnesses:

GEoRGE D. RICHARDS, BARBARA W. SUTTE'RLIN.

